The invention pertains to a cooling and/or heating device of the type described in the preamble of claim 1.
Such a cooling and/or heating device is known, for example, from EP 1 207 355 A2 and features a conduit network for at least one building with a main supply line. The main supply line is provided with a main flow conduit and a main return conduit. A fluid serves as the heat transfer medium or coolant in the conduit network. A heating circuit, a domestic water circuit and a ventilating circuit are connected to a distribution unit and feature heating/cooling sections with at least one valve each and at least one consuming device, e.g., a radiator/heat sink, a heat exchanger or the like. The distribution unit with the circuits connected thereto forms a supply unit. A valve arranged upstream or downstream of the supply unit is controlled as a function of the differential pressure between the supply conduit and return conduit. This differential pressure valve stabilizes the differential pressure between the supply conduit and return conduit of the supply unit such that the pressure in the supply unit can be maintained nearly constant and the supply units are uniformly supplied.
The individual circuits in the supply unit form so-called hydraulic circuits that can be either identical or configured differently.
EP 1 116 921 A2 also discloses a room air-conditioning system for buildings that comprises a device for heating and/or cooling a heat transfer medium and/or a coolant, several heat exchangers that release the heat of the medium into the surroundings and/or absorb the heat of the surroundings into the coolant, pipelines connecting the heat exchangers and the heating/cooling device to one another in order to transport the medium, and valves that are assigned to the heat exchangers and serve for adjusting the volumetric flow of the medium through the heat exchangers. A device for adjusting the medium pressure is also provided in order to vary the pressure of the medium. In addition, pressure sensors are assigned to the valves and actuators are provided for adjusting the valves. The device for adjusting the medium pressure makes it possible to obtain a central setpoint setting, for example, in order to centrally control a nighttime setback. Signals that switch the valves between nighttime setback and daytime settings are transmitted to pressure sensors in the form of predetermined pressure fluctuations. For this purpose, each pressure sensor features a sensor element that is moved as a function of the pressure of the medium, wherein said sensor element is mechanically, hydraulically, pneumatically or electrically coupled to the actuator of the valve and acts thereupon to adjust the valves. The valves are in this case provided in the form of thermostatic valves. This is intended to make it possible to switch the valve, for example, between nighttime setback and daytime settings independently of signal lines by means of the medium, such that the temperature setpoint is centrally adjusted.
Furthermore, DE 100 57 416 A1 discloses a central heating system for rooms to be heated in one or more buildings, wherein this system comprises a conduit network featuring flow and return conduits. Several heating sections are connected by means of supply and return conduits and are respectively provided with a valve for regulating/controlling the room temperature and at least one consuming device in the form of a radiator. In this case, each heating section features a flow restrictor that is arranged in the supply or return conduit of the heating section. This is intended to ensure a constant pressure level at the valves of each heating section.
The adjustment of a constant pressure level at the valves is referred to as hydraulic balancing. Hydraulic balancing makes it possible to ensure a sufficient water distribution in the conduit network under varying operating conditions without exceeding permissible noise levels. The utilization of section control valves, flow regulators, differential pressure regulators and a controlled circulating pump makes it possible to ensure an economical water distribution in the system by means of hydraulic balancing in accordance with the publication “IKZ-Haustechnik”, Vol. 13, p. 48 ff., 1999. Due to these measures, the required energy is made available to all consuming devices, namely radiators, heat exchangers and the like, at all times in the form of a uniform volumetric flow at the same setting, for example, of the thermostatic valves. If no hydraulic balancing takes place, the following problems arise in addition to increased energy consumption: the rooms do not reach the desired temperature, system components are heated only with a certain time delay, the room temperature also fluctuates in the part load mode, and noise develops at the valves.
A radiator/heat sink can only perform its function if it receives the optimal volumetric flow of the heat transfer medium or coolant. An excessively low volumetric flow results in a reduced heating/cooling capacity. However, excessive quantities of fluid delivered to a radiator/heat sink do not result in a proportional increase of the heating capacity, but rather only in slightly higher heat emission.
It is known to pre-adjust valves, i.e., to define the through-opening of the valves in order to provide hydraulic balancing. In this case, the valves act as throttles such that the pressure level upstream of all valves is also identical in the full load mode when all the valves of all heating/cooling sections are completely open.
However, known solutions for realizing hydraulic balancing are costly because they require additional construction measures. Furthermore, the volumetric flow is also limited by the valves, section gates or flow restrictors in the part load mode, for example, when no hydraulic balancing is required.